cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-8 of 8 results.

A129825 a(n) = n!*Bernoulli(n-1), n > 2; a(0)=0, a(1)=1, a(2)=1.

Original entry on oeis.org

0, 1, 1, 1, 0, -4, 0, 120, 0, -12096, 0, 3024000, 0, -1576143360, 0, 1525620096000, 0, -2522591034163200, 0, 6686974460694528000, 0, -27033456071346536448000, 0, 160078872315904478576640000, 0, -1342964491649083924630732800000, 0, 15522270327163593186886877184000000, 0
Offset: 0

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Author

Paul Curtz, Jun 03 2007

Keywords

Comments

Define "conjugated" Bernoulli numbers G(n) via G(0)=0, G(1)=B(0)=1, G(2)=-B(1)=1/2, G(n+1)=B(n), where B(n)=A027641(n)/A027642(n).
The sequence is then defined by a(n) = n!*G(n).
The first differences are 1, 0, 0, -1, -4, 4, 120, -120, -12096, ...
The 2nd differences are -1, 0, -1, -3, 8, 116, -240, -11976, 24192, 3011904, ...

Crossrefs

Equals second left hand column of A161739 (RSEG2 triangle).
Other left hand columns are A161742 and A161743.
Cf. A094310 [T(n,k) = n!/k], A008277 [S2(n,k); Stirling numbers of the second kind], A028246 [Worpitzky's triangle] and A008955 [CFN triangle].

Programs

  • Magma
    [n le 2 select Floor((n+1)/2) else Factorial(n)*Bernoulli(n-1): n in [0..40]]; // G. C. Greubel, Apr 26 2024
    
  • Maple
    A129825 := proc(n) if n <= 1 then n; elif n = 2 then 1; else n!*bernoulli(n-1) ; fi; end: # R. J. Mathar, May 21 2009
  • Mathematica
    a[n_] := n!*BernoulliB[n-1]; a[0]=0; a[2]=1; Table[a[n], {n, 0, 28}] (* Jean-François Alcover, Mar 04 2013 *)
  • SageMath
    [(n+1)//2 if n <3 else factorial(n)*bernoulli(n-1) for n in range(41)] # G. C. Greubel, Apr 26 2024

Formula

From Johannes W. Meijer, Jun 18 2009: (Start)
a(n) = Sum_{k=1..n} (-1)^(k+1)*(n!/k)*S2(n, k)*(k-1)!.
a(n) = Sum_{k=0..n-1} ((-1)^k/(k!*(k+1)!))*n!*A028246(n, k+1) *A008955(k, k). (End)
a(n) = A129814(n-1) for n > 2. - Georg Fischer, Oct 07 2018

Extensions

Edited by R. J. Mathar, May 21 2009

A001332 a(n) = Bernoulli(2*n) * (2*n + 1)!.

Original entry on oeis.org

1, 1, -4, 120, -12096, 3024000, -1576143360, 1525620096000, -2522591034163200, 6686974460694528000, -27033456071346536448000, 160078872315904478576640000, -1342964491649083924630732800000, 15522270327163593186886877184000000
Offset: 0

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Author

Keywords

References

  • G. S. Kazandzidis, On a Matrix and a Class of Polynomials, Bulletin de la Société Mathématique de Grèce, Nouvelle Série - Vol. 6 I, Fasc. 1, (1965), pp. 105-126.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A129814.

Programs

  • Mathematica
    Table[BernoulliB[2*n]*(2*n + 1)!, {n, 0, 20}] (* T. D. Noe, Jun 28 2012 *)
  • PARI
    {a(n) = if( n<0, 0, (2*n + 1)! * bernfrac( 2*n))} /* Michael Somos, Oct 08 2003 */

Formula

Lacunary e.g.f: x / (exp(x) - 1) + x / 2 = Sum_{k>=0} a(k) * x^(2*k) / ((2*k)! * (2*k + 1)!). - Michael Somos, Mar 29 2011
a(n) = determinant of the 2n X 2n matrix ( d(i,j) = binomial( i+1, i-j+2) if j < i+2 else 0 ). - Michael Somos, Oct 08 2003
a(n) = A129814(2*n). - Michael Somos, Mar 29 2011

A191578 Triangle read by rows, based on expansion of (x^2/(exp(x)-1))^m = x^m+sum(n>m T(n,m)*m!/((n-m)!*n!)*x^n).

Original entry on oeis.org

1, -1, 1, 1, -3, 1, 0, 10, -6, 1, -4, -30, 40, -10, 1, 0, 36, -270, 110, -15, 1, 120, 420, 1596, -1260, 245, -21, 1, 0, -2400, -5040, 14056, -4200, 476, -28, 1, -12096, -30240, -46080, -136080, 72576, -11340, 840, -36, 1, 0, 423360, 756000, 795600, -1197000, 276192, -26460, 1380, -45, 1, 3024000, 5987520, 4213440, 6098400, 17087400, -6652800, 857472, -55440, 2145, -55, 1, 0, -163296000, -251475840, -220651200, -158004000, 151169040, -27941760, 2297592, -106920, 3190, -66, 1
Offset: 1

Views

Author

Vladimir Kruchinin, Jun 07 2011

Keywords

Comments

1. Expansion of (x*Bernoulli(x)^m=x^m+sum(n>m m!*sum(k=1..n-m, (k!*stirling1(m+k,m)*stirling2(n-m,k))/(m+k)!))/(n-m)!*x^n)
2. Riordan Array (1,x*Bernoulli(x)) without first column.
3. Riordan Array (Bernoulli(x),x*Bernoulli(x)) numbering triangle (0,0).

Examples

			1,
-1,1,
1,-3,1,
0,10,-6,1,
-4,-30,40,-10,1,
0,36,-270,110,-15,1,
120,420,1596,-1260,245,-21,1
		

Crossrefs

First column T(n,1)=A129814(n-1)

Programs

  • Maple
    A191578 := proc(n, m)
        if m=n then
            1;
        else
            add(combinat[stirling2] (n-m, k) *k! *combinat[stirling1](m+k, m)/(m+k)!, k=1..n-m) ;
            %*n! ;
        end if;
    end proc: # R. J. Mathar, Jun 14 2013
  • Mathematica
    t[n_, m_] := n!*Sum[ (k!*StirlingS1[m+k, m]*StirlingS2[n-m, k])/(m+k)!, {k, 1, n-m}]; t[n_, n_] = 1; Table[t[n, m], {n, 1, 12}, {m, 1, n}] // Flatten (* Jean-François Alcover, Feb 22 2013 *)
  • Maxima
    T(n,m):=n!*sum((k!*stirling1(m+k,m)*stirling2(n-m,k))/(m+k)!,k,0,n-m); /* Vladimir Kruchinin, Jun 14 2013 */
    
  • Maxima
    T(n,m):=n!*(n-m)!/m!*sum(k!*binomial(m+k-1,m-1)*sum(((-1)^j*stirling2(n-m+j,j))/((k-j)!*(n-m+j)!),j,0,k),k,0,n-m); /* Vladimir Kruchinin, Jun 14 2013 */

Formula

T(n,m)=n!*sum(k=0..n-m, (k!*stirling1(m+k,m)*stirling2(n-m,k))/(m+k)!).
T(n,m):=n!*(n-m)!/m!*sum(k=0..n-m, k!*binomial(m+k-1,m-1)*sum(j=0..k, ((-1)^j*stirling2(n-m+j,j))/((k-j)!*(n-m+j)!))). [Vladimir Kruchinin, Jun 14 2013 ]

A273198 a(n) = T(n,2) with T(n, m) = (m*n+1)! * Sum_{k=0..n}( 1/(m*k+1) * Sum_{j=0..m*k} (-1)^j*C(k,j)*j^(m*n) ).

Original entry on oeis.org

1, -2, 296, -327984, 1363872384, -15198541159680, 372495898187043840, -17616182020373076940800, 1464370216956293433318604800, -199499758936277018742988067635200, 42181903584776412718275835664105472000, -13251216132203374725100642797337549799424000
Offset: 0

Views

Author

Peter Luschny, Jun 26 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[{1, Table[(2*n + 1)! * Sum[1/(2*k + 1)*Sum[(-1)^j*Binomial[k, j]*j^(2*n), {j, 0, 2*k}], {k, 0, n}], {n, 1, 10}]}] (* Vaclav Kotesovec, Jun 26 2016 *)
  • Sage
    def T(n, m): return factorial(m*n+1) * sum(1/(m*k+1)*sum((-1)^j*binomial(k,j)* j^(m*n) for j in (0..m*k)) for k in (0..n))
    def a(n): return T(n, 2)
    print([a(n) for n in (0..12)])

Formula

a(n) ~ (-1)^n * sqrt(Pi) * 2^(4*n) * n^(4*n + 1/2) / (sqrt(1-c) * exp(4*n) * c^n * (2-c)^(n-1)), where c = -LambertW(-2*exp(-2)) = -A226775 = 0.4063757399599599... . - Vaclav Kotesovec, Jun 26 2016

A356545 Triangle read by rows. T(n, k) are the coefficients of polynomials p_n(x) based on the Eulerian numbers of first order representing the Bernoulli numbers as B_n = p_n(1) / (n + 1)!.

Original entry on oeis.org

1, 1, 0, 2, -1, 0, 6, -8, 2, 0, 24, -66, 44, -6, 0, 120, -624, 792, -312, 24, 0, 720, -6840, 14496, -10872, 2736, -120, 0, 5040, -86400, 285840, -347904, 171504, -28800, 720, 0, 40320, -1244880, 6181920, -11245680, 8996544, -3090960, 355680, -5040, 0
Offset: 0

Views

Author

Peter Luschny, Aug 11 2022

Keywords

Comments

The Bernoulli numbers with B(1) = 1/2 can be represented as the weighted sum of Eulerian numbers, where we use the definition as given by Graham et al., Eulerian(n, k) = A173018(n, k). For n >= 0 we have
B_(n) = (1/(n + 1)) * Sum_{k=0..n} (-1)^k * Eulerian(n, k) / binomial(n, k).
The formula was given by Worpitsky in 1883 (see link) as an example for the application of a formula of Schlömilch from 1856. In 2019 the identity was proved in the modern fashion by Gessel on MathOverflow.
For a variant of this identity see the first formula in A356546.
An analogous representation based on the Eulerian numbers of second order is given in A356547.

Examples

			The table T(n, k) of the coefficients, sorted in ascending order, starts:
[0]     1;
[1]     1,        0;
[2]     2,       -1,       0;
[3]     6,       -8,       2,         0;
[4]    24,      -66,      44,        -6,       0;
[5]   120,     -624,     792,      -312,      24,        0;
[6]   720,    -6840,   14496,    -10872,    2736,     -120,      0;
[7]  5040,   -86400,  285840,   -347904,  171504,   -28800,    720,     0;
[8] 40320, -1244880, 6181920, -11245680, 8996544, -3090960, 355680, -5040, 0;
		

References

  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics, 2nd ed. Addison-Wesley, Reading, MA, 1994, p. 268. (Since the thirty-fourth printing, Jan. 2022, with B(1) = 1/2.)

Crossrefs

Cf. A173018 (Eulerian number), A164555(n)/A027642(n) (Bernoulli numbers with B(1) = 1/2), A129814 (row sums, but different sign for n = 1).

Programs

  • Maple
    E1 := proc(n, k) combinat:-eulerian1(n, k) end:
    p := (n, x) -> add(E1(n, k)*k!*(n - k)!*(-x)^k, k = 0..n):
    seq(print(seq(coeff(p(n, x), x, k), k=0..n)), n = 0..8);
    seq(p(n, 1)/(n + 1)!, n = 0..14); # check the Bernoulli representation
  • Mathematica
    T[n_, k_] := k! * (n-k)! * Sum[(-1)^(k-j) * (k-j+1)^n * Binomial[n+1, j], {j, 0, k}]; Table[T[n, k], {n, 0, 9}, {k, 0, n}] // TableForm
    (* Diagonals: *)
    d[n_, k_] := k! * (n - k)! * Sum[(-1)^(n-k-j)*(n - j - k + 1)^n * Binomial[n + 1, j], {j, 0, n - k}];

Formula

Let p_n(x) = Sum_{k=0..n} Eulerian(n, k)*k!*(n - k)! * (-x)^k. For x = 1 these polynomials give rise to the representation Bernoulli(n) = p_n(1) / (n + 1)!.
T(n, k) = [x^k] p_n(x).
T(n, k) = (-1)^k*Eulerian(n, k)*k!*(n - k)!.
T(n, k) = k! * (n-k)! * Sum_{j=0..k} (-1)^(k-j)*(k-j+1)^n*binomial(n+1, j).
T(n, k) = (-1)^k * A173018(n, k) * A098361(n, k).
T(n, k) = (-1)^k * A123125(n, n - k) * A098361(n, n - k).

A137777 Triangular sequence of coefficients from the expansion of the derivative of the Bernoulli polynomial function: p(x,t) = t*exp(x*t)/(exp(t)-1); q(x,t) = p'(x,t) = dp(x,t)/dt.

Original entry on oeis.org

2, -2, 4, 2, -12, 12, 0, 24, -72, 48, -8, 0, 240, -480, 240, 0, -240, 0, 2400, -3600, 1440, 240, 0, -5040, 0, 25200, -30240, 10080, 0, 13440, 0, -94080, 0, 282240, -282240, 80640, -24192, 0, 483840, 0, -1693440, 0, 3386880, -2903040, 725760, 0, -2177280, 0, 14515200, 0, -30481920, 0, 43545600, -32659200
Offset: 0

Views

Author

Keywords

Comments

Row sums are {2, 2, 0, -8, 0, 240, 0, -24192, 0, 6048000, 0, ...}.
From Peter Luschny, Apr 23 2009: (Start)
The sequence can also be computed as the coefficients of the Bernoulli polynomials B_n(x) times 2(n+1)! for n >= 1. As Peter Pein observed the Mathematica code then reduces to
Table[CoefficientList[2 (n+1)! BernoulliB[n,x],x],{n,1,10}] // Flatten
Note that this formula is also well defined in the case n = 0 and has the value 2. (End)

Examples

			{2},
{-2, 4},
{2, -12, 12},
{0,24, -72, 48},
{-8, 0, 240, -480, 240},
{0, -240, 0, 2400, -3600, 1440},
{240, 0, -5040, 0, 25200, -30240, 10080},
{0, 13440, 0, -94080, 0, 282240, -282240, 80640},
{-24192, 0, 483840, 0, -1693440, 0, 3386880, -2903040, 725760},
{0, -2177280, 0, 14515200, 0, -30481920, 0, 43545600, -32659200, 7257600},
{6048000, 0, -119750400, 0, 399168000, 0, -558835200, 0, 598752000, -399168000, 79833600},
{0, 798336000, 0, -5269017600, 0, 10538035200, 0, -10538035200, 0, 8781696000, -5269017600, 958003200}
		

Programs

  • Maple
    seq(seq(coeff(bernoulli(k,x)*2*(k+1)!,x,i),i=0..k),k=1..10); # Peter Luschny, Apr 23 2009
  • Mathematica
    Clear[p, b, a]; p[t_] = D[t^2*Exp[x*t]/(Exp[t]-1),{t,1}];
    a = Table[CoefficientList[2*n!^2*SeriesCoefficient
    [Series[p[t],{t,0,30}],n],x],{n,0,10}]; Flatten[a]
    Table[CoefficientList[2 BernoulliB[k,x] Gamma[2+k],x],{k,0,10}]//Flatten

Formula

p(x,t) = t*exp(x*t)/(exp(t)-1); q(x,t) = p'(x,t) = dp(x,t)/dt = Sum_{n>=0} Q(x,n)*t^n/n!; out_n,m=2*(n + 2)!*n!*Coefficients(Q(x,n).
A137777(n,0) = 2*A129814(n) for n >= 0.
A137777(n,n) = 2*(n+1)! for n >= 0.
Conjecture on row sums: Sum_{k=0..n+1} T(n,k) = 2*A129825(n+2). - R. J. Mathar, Jun 03 2009

Extensions

Edited by N. J. A. Sloane, Jan 03 2010, incorporating comments from Peter Luschny and Peter Pein

A273196 a(n) = numerator of T(n, 2) with T(n, m) = Sum_{k=0..n}( 1/(m*k+1) * Sum_{j=0..m*k} (-1)^j*C(k,j)*j^(m*n) ).

Original entry on oeis.org

1, -1, 37, -6833, 56377, -439772603, 27217772209, -202070742359, 80837575181815013, -155957202651688954367, 1770963292969902374951, -16092436217742770647634507, 2975968726866580246152132993, -963399772945511487665759472653, 3891037048609240492066339458106680163
Offset: 0

Views

Author

Peter Luschny, Jun 26 2016

Keywords

Comments

T(n,0) are the natural numbers, T(n,1) the Bernoulli numbers.

Crossrefs

Cf. A273197 (denominator), T(n,0) = A000027, T(n,1) = A027641/A027642.
Also T(n,1)*(1*n+1)! = A129814, T(n,2)*(2*n+1)! = A273198.

Programs

  • Mathematica
    Table[Function[{n, m}, If[n == 0, 1, Numerator@ Sum[1/(m k + 1) Sum[(-1)^j Binomial[k, j] j^(m n), {j, 0, m k}], {k, 0, n}]]][n, 2], {n, 0, 14}] (* Michael De Vlieger, Jun 26 2016 *)
  • Sage
    def T(n, m): return sum(1/(m*k+1)*sum((-1)^j*binomial(k,j)*j^(m*n) for j in (0..m*k)) for k in (0..n))
    def a(n): return T(n, 2).numerator()
    print([a(n) for n in (0..14)])

A273197 a(n) = denominator of T(n, 2) with T(n, m) = Sum_{k=0..n}( 1/(m*k+1) * Sum_{j=0..m*k} (-1)^j*C(k,j)*j^(m*n) ).

Original entry on oeis.org

1, 3, 15, 105, 15, 1155, 455, 15, 19635, 95095, 2145, 31395, 7735, 2805, 10818885, 50115065, 3315, 596505, 80925845, 3795, 18515805, 221847535, 2211105, 204920500785, 1453336885, 148335, 95055765, 287558635, 27897511785, 397299047145, 5613813089885, 8897205
Offset: 0

Views

Author

Peter Luschny, Jun 26 2016

Keywords

Comments

T(n,0) are the natural numbers, T(n,1) the Bernoulli numbers.

Crossrefs

Cf. A273196 (numerators).
T(n,0) = A000027(n) for n>=1.
T(n,1) = A027641(n)/A027642(n) for all n>=0.
T(n,1)*(1*n+1)! = A129814(n) for all n>=0.
T(n,2)*(2*n+1)! = A273198(n) for all n>=0.

Programs

  • Mathematica
    Table[Function[{n, m}, If[n == 0, 1, Denominator@ Sum[1/(m k + 1) Sum[(-1)^j Binomial[k, j] j^(m n), {j, 0, m k}], {k, 0, n}]]][n, 2], {n, 0, 31}] (* Michael De Vlieger, Jun 26 2016 *)
  • Sage
    def T(n, m): return sum(1/(m*k+1)*sum((-1)^j*binomial(k,j)*j^(m*n) for j in (0..m*k)) for k in (0..n))
    def a(n): return T(n, 2).denominator()
    print([a(n) for n in (0..31)])
Showing 1-8 of 8 results.